The Domain Name System (DNS) is a decentralized naming system for resources (e.g., computers, services, etc.) that are connected to the Internet. In general, the DNS operates to translate/resolve human-readable hostnames associated with a resource, sometimes referred to herein as domain names, into a numerical network address (e.g., an Internet Protocol (IP) address) that is needed to locate and identify the resource with the underlying network protocols.
The DNS is maintained as a distributed database system that makes use of the client-server model. The nodes of this database are the name servers, where each domain has at least one authoritative name server that publishes information about that domain and about any name servers of any domains subordinate thereto. DNS resolvers form the client side of the DNS. A DNS resolver is responsible for initiating and sequencing the queries that lead to a full resolution (translation) of the resource sought (e.g., translation of a domain name into a network address).